There is a tape drive device that writes data to magnetic tape in order to record and store data outputted from an arithmetic processing unit such as a server. To cope with the tendency of increasing amount of data in recent years, a tape library device which contains a large number of tape drive devices in one housing is provided. In the tape library device, a robot mechanism that receives a command puts a tape into and takes a tape out of each tape drive device.
A door of the tape library device is provided with an interlock mechanism so that an operator such as a worker who performs maintenance of the tape library (hereinafter simply referred to as an “operator”) does not touch the robot mechanism that is operating. When the door of the tape library device is opened, the interlock mechanism shuts off power supply of the robot mechanism to stop the robot mechanism.
When a failure occurs in the library device, if the operator opens the door to check the state of the device, the power supply of the robot mechanism is shut down. Therefore, when the operator checks the state of the robot mechanism, the operator temporarily turns on the interlock switch by using a tool to disable the interlock and thereafter checks the state of the robot mechanism. The robot mechanism whose power is turned on again returns to normal operation after performing an initialization operation, so that the operator waits until the initialization operation is completed to check the operation of the robot mechanism. Further, when the initialization operation is performed, the state of the robot mechanism changes from the state of the time when the failure occurs, so that it is difficult for the operator to check the state of the time when the failure occurs without change.
Further, in recent years, in order to manage more tapes, a tape library device is provided in which a plurality of tape library devices are connected and a conveyance mechanism that moves tapes between the devices is installed. Conventionally, in the device in which a plurality of tape library devices are connected, when a door of any one of the tape library devices is opened, along with the power supply of the robot mechanism of the tape library device whose door is opened, the power supply of the conveyance mechanism is shut off and the conveyance mechanism is stopped by the interlock mechanism. Therefore, it is not possible to move storage media between the tape library devices whose doors are not opened.
A conventional technique is proposed in which the interlock is logically disabled by performing control using a circuit or the like in order to secure a continuity of the device operation.
Patent Document 1: Japanese Laid-open Patent Publication No. 2000-164480
Patent Document 2: Japanese Laid-open Patent Publication No. 2006-12912
Patent Document 3: Japanese Laid-open Patent Publication No. 2005-175125
However, in the conventional technique which logically disables the interlock by performing control, a mechanism including a circuit to control the interlock has to be additionally provided. Therefore, if the conventional technique is used, the manufacturing cost increases by newly manufacturing a control mechanism. Further, manufacturing and assembling of the control mechanism occur in addition to those of the interlock mechanism, so that the manufacturing process is complicated. Further, it is necessary to test a disabling mechanism to secure safety and a method of testing a logical disabling mechanism is complicated, so that the cost increases from this point.